 /*******************************************************************************
  * Copyright (c) 2004 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Common Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/cpl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/

 package org.eclipse.osgi.framework.internal.defaultadaptor;

 import java.io.*;
 import java.net.URL ;
 import java.security.ProtectionDomain ;
 import java.util.*;
 import org.eclipse.osgi.framework.adaptor.ClassLoaderDelegate;
 import org.eclipse.osgi.framework.adaptor.core.*;
 import org.eclipse.osgi.framework.debug.Debug;
 import org.osgi.framework.BundleException;
 import org.osgi.framework.FrameworkEvent;

 /**
  * A concrete implementation of BundleClassLoader. This implementation
  * consolidates all Bundle-ClassPath entries into a single ClassLoader.
  */
 public class DefaultClassLoader extends AbstractClassLoader {
     /**
      * The BundleData object for this BundleClassLoader
      */
     protected AbstractBundleData hostdata;

     /**
      * The ClasspathEntries for this BundleClassLoader. Each ClasspathEntry object
      * represents on Bundle-ClassPath entry.
      */
     protected ClasspathEntry[] classpathEntries;

     protected Vector fragClasspaths; //TODO This should be an array or an arraylist if the synchronization is not required

     /**
      * The buffer size to use when loading classes. This value is used
      * only if we cannot determine the size of the class we are loading.
      */
     protected int buffersize = 8 * 1024;

     /**
      * BundleClassLoader constructor.
      * @param delegate The ClassLoaderDelegate for this ClassLoader.
      * @param domain The ProtectionDomain for this ClassLoader.
      * @param classpath An array of Bundle-ClassPath entries to
      * use for loading classes and resources. This is specified by the
      * Bundle-ClassPath manifest entry.
      * @param parent The parent ClassLoader.
      * @param bundledata The BundleData for this ClassLoader
      */
     public DefaultClassLoader(ClassLoaderDelegate delegate, ProtectionDomain domain, String [] classpath, ClassLoader parent, AbstractBundleData bundledata) {
         super(delegate, domain, classpath, parent);
         this.hostdata = bundledata;

         try {
             hostdata.open(); /* make sure the BundleData is open */
         } catch (IOException e) {
             hostdata.getAdaptor().getEventPublisher().publishFrameworkEvent(FrameworkEvent.ERROR, hostdata.getBundle(), e);
         }
     }

     public void initialize() {
         classpathEntries = buildClasspath(hostclasspath, hostdata, hostdomain);
     }

     /**
      * Attaches the BundleData for a fragment to this BundleClassLoader.
      * The Fragment BundleData resources must be appended to the end of
      * this BundleClassLoader's classpath. Fragment BundleData resources
      * must be searched ordered by Bundle ID's.
      * @param bundledata The BundleData of the fragment.
      * @param domain The ProtectionDomain of the resources of the fragment.
      * Any classes loaded from the fragment's BundleData must belong to this
      * ProtectionDomain.
      * @param classpath An array of Bundle-ClassPath entries to
      * use for loading classes and resources. This is specified by the
      * Bundle-ClassPath manifest entry of the fragment.
      */
     public void attachFragment(org.eclipse.osgi.framework.adaptor.BundleData bundledata, ProtectionDomain domain, String [] classpath) {
         AbstractBundleData abstractbundledata = (AbstractBundleData) bundledata;
         try {
             bundledata.open(); /* make sure the BundleData is open */
         } catch (IOException e) {

             abstractbundledata.getAdaptor().getEventPublisher().publishFrameworkEvent(FrameworkEvent.ERROR, abstractbundledata.getBundle(), e);
         }
         ClasspathEntry[] fragEntries = buildClasspath(classpath, abstractbundledata, domain);
         FragmentClasspath fragClasspath = new FragmentClasspath(fragEntries, abstractbundledata, domain);
         insertFragment(fragClasspath);
     }

     /**
      * Inserts a fragment classpath to into the list of fragments for this host.
      * Fragments are inserted into the list according to the fragment's
      * Bundle ID.
      * @param fragClasspath The FragmentClasspath to insert.
      */
     protected synchronized void insertFragment(FragmentClasspath fragClasspath) {
         if (fragClasspaths == null) {
             // First fragment to attach. Simply create the list and add the fragment.
 fragClasspaths = new Vector(10);
             fragClasspaths.addElement(fragClasspath);
             return;
         }

         // Find a place in the fragment list to insert this fragment.
 int size = fragClasspaths.size();
         long fragID = fragClasspath.bundledata.getBundleID();
         for (int i = 0; i < size; i++) {
             long otherID = ((FragmentClasspath) fragClasspaths.elementAt(i)).bundledata.getBundleID();
             if (fragID < otherID) {
                 fragClasspaths.insertElementAt(fragClasspath, i);
                 return;
             }
         }
         // This fragment has the highest ID; put it at the end of the list.
 fragClasspaths.addElement(fragClasspath);
     }

     /**
      * Gets a ClasspathEntry object for the specified ClassPath entry.
      * @param cp The ClassPath entry to get the ClasspathEntry for.
      * @param bundledata The BundleData that the ClassPath entry is for.
      * @param domain The ProtectionDomain for the ClassPath entry.
      * @return The ClasspathEntry object for the ClassPath entry.
      */
     protected ClasspathEntry getClasspath(String cp, AbstractBundleData bundledata, ProtectionDomain domain) {
         BundleFile bundlefile = null;
         File file = bundledata.getBaseBundleFile().getFile(cp);
         if (file != null && file.exists()) {
             try {
                 bundlefile = hostdata.getAdaptor().createBundleFile(file, bundledata);
             } catch (IOException e) {
                 bundledata.getAdaptor().getEventPublisher().publishFrameworkEvent(FrameworkEvent.ERROR, bundledata.getBundle(), e);
             }
         } else if (bundledata.getBaseBundleFile().containsDir(cp)) {
             // the classpath entry is a directory in the bundle jar file.
 bundlefile = new BundleFile.NestedDirBundleFile(bundledata.getBaseBundleFile(), cp);
         }

         // if in dev mode, try using the cp as an absolute path
 if (bundlefile == null && DevClassPathHelper.inDevelopmentMode()) {
             file = new File(cp);
             if (file.exists() && file.isAbsolute())
                 // if the file exists and is absolute then create BundleFile for it.
 try {
                     bundlefile = hostdata.getAdaptor().createBundleFile(file, bundledata);
                 } catch (IOException e) {
                     bundledata.getAdaptor().getEventPublisher().publishFrameworkEvent(FrameworkEvent.ERROR, bundledata.getBundle(), e);
                 }
         }

         if (bundlefile != null)
             return createClassPathEntry(bundlefile, domain);
         else
             return null;
     }

     protected synchronized Class findClass(String name) throws ClassNotFoundException {
         Class result = findLoadedClass(name);
         if (result != null)
             return result;
         for (int i = 0; i < classpathEntries.length; i++) {
             if (classpathEntries[i] != null) {
                 result = findClassImpl(name, classpathEntries[i]);
                 if (result != null) {
                     return result;
                 }
             }
         }
         // look in fragments.
 if (fragClasspaths != null) {
             int size = fragClasspaths.size();
             for (int i = 0; i < size; i++) {
                 FragmentClasspath fragCP = (FragmentClasspath) fragClasspaths.elementAt(i);
                 for (int j = 0; j < fragCP.classpathEntries.length; j++) {
                     result = findClassImpl(name, fragCP.classpathEntries[j]);
                     if (result != null) {
                         return result;
                     }
                 }
             }
         }
         throw new ClassNotFoundException (name);
     }

     /**
      * Finds a class in the BundleFile. If a class is found then the class
      * is defined using the ProtectionDomain bundledomain.
      * @param name The name of the class to find.
      * @param classpathEntry The ClasspathEntry to find the class in.
      * @return The loaded class object or null if the class is not found.
      */
     protected Class findClassImpl(String name, ClasspathEntry classpathEntry) {
         if (Debug.DEBUG && Debug.DEBUG_LOADER) {
             Debug.println("BundleClassLoader[" + hostdata + "].findClass(" + name + ")"); //$NON-NLS-1$ //$NON-NLS-2$//$NON-NLS-3$
 }

         String filename = name.replace('.', '/').concat(".class"); //$NON-NLS-1$

         BundleEntry entry = classpathEntry.getBundleFile().getEntry(filename);

         if (entry == null) {
             return null;
         }

         InputStream in;
         try {
             in = entry.getInputStream();
         } catch (IOException e) {
             return null;
         }

         int length = (int) entry.getSize();
         byte[] classbytes;
         int bytesread = 0;
         int readcount;

         if (Debug.DEBUG && Debug.DEBUG_LOADER) {
             Debug.println(" about to read " + length + " bytes from " + filename); //$NON-NLS-1$ //$NON-NLS-2$
 }

         try {
             try {
                 if (length > 0) {
                     classbytes = new byte[length];

                     readloop: for (; bytesread < length; bytesread += readcount) {
                         readcount = in.read(classbytes, bytesread, length - bytesread);

                         if (readcount <= 0) /* if we didn't read anything */{
                             break readloop; /* leave the loop */
                         }
                     }
                 } else /* BundleEntry does not know its own length! */{
                     length = buffersize;
                     classbytes = new byte[length];

                     readloop: while (true) {
                         for (; bytesread < length; bytesread += readcount) {
                             readcount = in.read(classbytes, bytesread, length - bytesread);

                             if (readcount <= 0) /* if we didn't read anything */{
                                 break readloop; /* leave the loop */
                             }
                         }

                         byte[] oldbytes = classbytes;
                         length += buffersize;
                         classbytes = new byte[length];
                         System.arraycopy(oldbytes, 0, classbytes, 0, bytesread);
                     }
                 }
             } catch (IOException e) {
                 if (Debug.DEBUG && Debug.DEBUG_LOADER) {
                     Debug.println(" IOException reading " + filename + " from " + hostdata); //$NON-NLS-1$ //$NON-NLS-2$
 }

                 return null;
             }
         } finally {
             try {
                 in.close();
             } catch (IOException ee) {
             }
         }

         if (Debug.DEBUG && Debug.DEBUG_LOADER) {
             Debug.println(" read " + bytesread + " bytes from " + filename); //$NON-NLS-1$ //$NON-NLS-2$
 Debug.println(" defining class " + name); //$NON-NLS-1$
 }

         try {
             return (defineClass(name, classbytes, 0, bytesread, classpathEntry));
         } catch (Error e) {
             if (Debug.DEBUG && Debug.DEBUG_LOADER) {
                 Debug.println(" error defining class " + name); //$NON-NLS-1$
 }

             throw e;
         }
     }

     protected Class defineClass(String name, byte[] classbytes, int off, int len, ClasspathEntry classpathEntry) throws ClassFormatError {
         if (name != null && name.startsWith("java.")) { //$NON-NLS-1$
 // To work around the security issue that prevents any
 // other classloader except for the bootstrap classloader
 // from loading packages that start with java.
 name = null;
         }
         return defineClass(name, classbytes, off, len, classpathEntry.getProtectionDomain());
     }

     protected URL findResource(String name) {
         URL result = null;
         for (int i = 0; i < classpathEntries.length; i++) {
             if (classpathEntries[i] != null) {
                 result = findResourceImpl(name, classpathEntries[i].getBundleFile());
                 if (result != null) {
                     return result;
                 }
             }
         }
         // look in fragments
 if (fragClasspaths != null) {
             int size = fragClasspaths.size();
             for (int i = 0; i < size; i++) {
                 FragmentClasspath fragCP = (FragmentClasspath) fragClasspaths.elementAt(i);
                 for (int j = 0; j < fragCP.classpathEntries.length; j++) {
                     result = findResourceImpl(name, fragCP.classpathEntries[j].getBundleFile());
                     if (result != null) {
                         return result;
                     }
                 }
             }
         }
         return null;
     }

     /**
      * Looks in the specified BundleFile for the resource.
      * @param name The name of the resource to find,.
      * @param bundlefile The BundleFile to look in.
      * @return A URL to the resource or null if the resource does not exist.
      */
     protected URL findResourceImpl(String name, BundleFile bundlefile) {
         return bundlefile.getResourceURL(name, hostdata.getBundleID());
     }

     /**
      * @see org.eclipse.osgi.framework.adaptor.BundleClassLoader#findLocalResources(String)
      */
     public Enumeration findLocalResources(String resource) {
         Vector resources = new Vector(6);
         for (int i = 0; i < classpathEntries.length; i++) {
             if (classpathEntries[i] != null) {
                 URL url = findResourceImpl(resource, classpathEntries[i].getBundleFile());
                 if (url != null) {
                     resources.addElement(url);
                 }
             }
         }
         // look in fragments
 if (fragClasspaths != null) {
             int size = fragClasspaths.size();
             for (int i = 0; i < size; i++) {
                 FragmentClasspath fragCP = (FragmentClasspath) fragClasspaths.elementAt(i);
                 for (int j = 0; j < fragCP.classpathEntries.length; j++) {
                     URL url = findResourceImpl(resource, fragCP.classpathEntries[j].getBundleFile());
                     if (url != null) {
                         resources.addElement(url);
                     }
                 }
             }
         }
         if (resources.size() > 0) {
             return resources.elements();
         }
         return null;
     }

     public Object findLocalObject(String object) {
         BundleEntry result = null;
         for (int i = 0; i < classpathEntries.length; i++) {
             if (classpathEntries[i] != null) {
                 result = findObjectImpl(object, classpathEntries[i].getBundleFile());
                 if (result != null) {
                     return result;
                 }
             }
         }
         // look in fragments
 if (fragClasspaths != null) {
             int size = fragClasspaths.size();
             for (int i = 0; i < size; i++) {
                 FragmentClasspath fragCP = (FragmentClasspath) fragClasspaths.elementAt(i);
                 for (int j = 0; j < fragCP.classpathEntries.length; j++) {
                     result = findObjectImpl(object, fragCP.classpathEntries[j].getBundleFile());
                     if (result != null) {
                         return result;
                     }
                 }
             }
         }
         return null;
     }

     protected BundleEntry findObjectImpl(String object, BundleFile bundleFile) {
         return bundleFile.getEntry(object);
     }

     /**
      * Closes all the BundleFile objects for this BundleClassLoader.
      */
     public void close() {
         // do not close if we are shutting down
 if (closed || hostdata.getAdaptor().isStopping())
             return;

         super.close();
         if (classpathEntries != null) {
             for (int i = 0; i < classpathEntries.length; i++) {
                 if (classpathEntries[i] != null) {
                     try {
                         if (classpathEntries[i].getBundleFile() != hostdata.getBaseBundleFile()) {
                             classpathEntries[i].getBundleFile().close();
                         }
                     } catch (IOException e) {
                         hostdata.getAdaptor().getEventPublisher().publishFrameworkEvent(FrameworkEvent.ERROR, hostdata.getBundle(), e);
                     }
                 }
             }
         }
         if (fragClasspaths != null) {
             int size = fragClasspaths.size();
             for (int i = 0; i < size; i++) {
                 FragmentClasspath fragCP = (FragmentClasspath) fragClasspaths.elementAt(i);
                 fragCP.close();
             }
         }
     }

     protected ClasspathEntry[] buildClasspath(String [] classpath, AbstractBundleData bundledata, ProtectionDomain domain) {
         ArrayList result = new ArrayList(10);

         // If not in dev mode then just add the regular classpath entries and return
 if (!DevClassPathHelper.inDevelopmentMode()) {
             for (int i = 0; i < classpath.length; i++)
                 findClassPathEntry(result, classpath[i], bundledata, domain);
             return (ClasspathEntry[]) result.toArray(new ClasspathEntry[result.size()]);
         }

         // Otherwise, add the legacy entries for backwards compatibility and
 // then for each classpath entry add the dev entries as spec'd in the
 // corresponding properties file. If none are spec'd, add the
 // classpath entry itself
 addDefaultDevEntries(result, bundledata, domain);
         for (int i = 0; i < classpath.length; i++) {
             String [] devEntries = getDevEntries(classpath[i], bundledata);
             if (devEntries != null && devEntries.length > 0) {
                 for (int j = 0; j < devEntries.length; j++)
                     findClassPathEntry(result, devEntries[j], bundledata, domain);
             } else
                 findClassPathEntry(result, classpath[i], bundledata, domain);
         }
         return (ClasspathEntry[]) result.toArray(new ClasspathEntry[result.size()]);
     }

     protected void addDefaultDevEntries(ArrayList result, AbstractBundleData bundledata, ProtectionDomain domain) {
         String [] devClassPath = DevClassPathHelper.getDevClassPath(bundledata.getSymbolicName());
         if (devClassPath == null)
             return;
         for (int i = 0; i < devClassPath.length; i++)
             findClassPathEntry(result, devClassPath[i], bundledata, domain);
     }

     protected void findClassPathEntry(ArrayList result, String entry, AbstractBundleData bundledata, ProtectionDomain domain) {
         if (!addClassPathEntry(result, entry, bundledata, domain)) {
             // if (devCP == null) {
 // BundleException be = new BundleException(Msg.formatter.getString("BUNDLE_CLASSPATH_ENTRY_NOT_FOUND_EXCEPTION", entry, hostdata.getLocation()));
 // bundledata.getAdaptor().getEventPublisher().publishFrameworkEvent(FrameworkEvent.ERROR, bundledata.getBundle(), be);
 // }
 }
     }

     protected boolean addClassPathEntry(ArrayList result, String entry, AbstractBundleData bundledata, ProtectionDomain domain) {
         if (entry.equals(".")) { //$NON-NLS-1$
 result.add(createClassPathEntry(bundledata.getBaseBundleFile(), domain));
             return true;
         }
         Object element = getClasspath(entry, bundledata, domain);
         if (element != null) {
             result.add(element);
             return true;
         }
         // need to check in fragments for the classpath entry.
 // only check for fragments if the bundledata is the hostdata.
 if (fragClasspaths != null && hostdata == bundledata) {
             int size = fragClasspaths.size();
             for (int i = 0; i < size; i++) {
                 FragmentClasspath fragCP = (FragmentClasspath) fragClasspaths.elementAt(i);
                 element = getClasspath(entry, fragCP.bundledata, fragCP.domain);
                 if (element != null) {
                     result.add(element);
                     return true;
                 }
             }
         }
         return false;
     }

     protected String [] getDevEntries(String classpathEntry, AbstractBundleData bundledata) {
         File propLocation = bundledata.getBaseBundleFile().getFile(classpathEntry + ".properties"); //$NON-NLS-1$
 if (propLocation == null)
             return null;
         try {
             InputStream in = new FileInputStream(propLocation);
             try {
                 Properties devProps = new Properties();
                 devProps.load(in);
                 return DevClassPathHelper.getArrayFromList(devProps.getProperty("bin")); //$NON-NLS-1$
 } finally {
                 in.close();
             }
         } catch (IOException e) {
             BundleException be = new BundleException(AdaptorMsg.formatter.getString("BUNDLE_CLASSPATH_PROPERTIES_ERROR", propLocation), e); //$NON-NLS-1$
 bundledata.getAdaptor().getEventPublisher().publishFrameworkEvent(FrameworkEvent.ERROR, bundledata.getBundle(), be);
         }
         return null;
     }

     /**
      * Creates a ClasspathEntry from a BundleFile and ProtectionDomain.
      * @param bundlefile the BundleFile.
      * @param domain the ProtectionDomain
      * @return the ClasspathEntry
      */
     protected ClasspathEntry createClassPathEntry(BundleFile bundlefile, ProtectionDomain domain) {
         return new ClasspathEntry(bundlefile, domain);
     }

     /**
      * A data structure to hold information about a fragment classpath.
      */
     protected class FragmentClasspath {
         /** The ClasspathEntries of the fragments Bundle-Classpath */
         protected ClasspathEntry[] classpathEntries;
         /** The BundleData of the fragment */
         protected AbstractBundleData bundledata;
         /** The ProtectionDomain of the fragment */
         protected ProtectionDomain domain;

         protected FragmentClasspath(ClasspathEntry[] classpathEntries, AbstractBundleData bundledata, ProtectionDomain domain) {
             this.classpathEntries = classpathEntries;
             this.bundledata = bundledata;
             this.domain = domain;
         }

         protected void close() {
             for (int i = 0; i < classpathEntries.length; i++) {
                 try {
                     if (classpathEntries[i].getBundleFile() != bundledata.getBaseBundleFile()) {
                         classpathEntries[i].getBundleFile().close();
                     }
                 } catch (IOException e) {
                     bundledata.getAdaptor().getEventPublisher().publishFrameworkEvent(FrameworkEvent.ERROR, bundledata.getBundle(), e);
                 }
             }
         }
     }

     /**
      * A data structure to hold information about a classpath entry.
      */
     protected class ClasspathEntry {
         protected BundleFile bundlefile;
         protected ProtectionDomain domain;

         protected ClasspathEntry(BundleFile bundlefile, ProtectionDomain domain) {
             this.bundlefile = bundlefile;
             this.domain = domain;
         }

         public BundleFile getBundleFile() {
             return bundlefile;
         }

         public ProtectionDomain getProtectionDomain() {
             return domain;
         }
     }
 }
